可燃液体雾滴粒径分布对其引燃性的影响
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摘要
为了深入了解可燃液体雾滴粒径分布对其在空气中引燃特性的影响,利用Winner38C激光粒度分析仪和喷射系统,并借助自行设计和建造的立式爆炸管,对航空煤油雾滴粒径分布的燃烧特性进行了试验研究。首先,测量了5个喷嘴在不同喷射压力下,航空煤油雾滴粒径的变化情况;其次,在氧初始体积分数为21%时,分别使用2种不同点火系统对航空煤油雾滴进行了点燃试验。结果表明,随喷射压力增大,航空煤油雾滴索特平均直径变小,最小索特平均直径为15μm。熔丝点火试验发现点火延迟时间对雾滴燃烧有很大的影响,航空煤油雾滴的燃烧或爆炸不仅与粒径有关,还与雾滴的浓度有很大关系。在点火能分别为155 mJ、165 mJ、175 mJ、185 mJ、195 mJ时对雾滴进行静电点火引燃试验,得出随着小粒径占比逐渐升高,点火能逐渐降低,同时得出航空煤油索特平均直径D32与最小点火能之间的关系。
The article is to present the experimental testing results of the combustion characteristics of the droplet size distribution of aviation kerosene were with a Winner38 C laser particle size analyzer and the injection system. For the study purpose,we have also designed and constructed a vertical explosive tube by the authors ourselves so as to identify and determined the effects of the droplet size distribution of the combustible liquid on its ignition features of the atmosphere. In proceeding with our experiments,we have first of all managed to measure the variation of the droplet sizes of the aviation kerosene at the different injection pressures of the 5 nozzles. And,secondly,the ignition test of the aviation kerosene droplets has been conducted in the two different firing systems with the initial oxygen concentration being 21%.The results of the afforementioned experiments and tests indicate that,with the increase of the injection pressure the Sauter mean diameter( SMD) of the aerosol droplets tends to decrease,with the minimum SMD of aviation kerosene droplet being of 15 μm. However,the particle size distribution of the mist droplets remains unchanged with the increase of the pressure for the mechanical crushing capacity of the atomizing nozzle would be saturated. Further fuse ignition tests we have done help us to discover that the ignition delay ought to have had a tremendous impact on the combustion of the droplets,for the combustion or explosion of the aviation kerosene droplets is not only related to the particle size,but also is closely related to the concentration of the said droplets,because the height of the flame and the explosion status-in-situ can greatly been influenced and reduced due to the delay of ignition time. For instance,when the concentration of the droplets is reduced to a certain extent,it would not be able to get ignited. A clear example can be seen that,when we conducted the electrostatic ignition tests with the droplets at the ignition energy of 155 mJ,165 mJ,175 mJ,185 mJ and 195 mJ,respectively and correspondingly. Thus,it can be concluded that the ignition energy tends to gradually decrease with the increase of the proportion of the small particle sizes. Furthermore,we have also examined and clarified the relationship between the SMD of D32 and the minimum ignition,which let us believe that there ought to exist a clear inverse proportion between the minimum ignition energy and the SMD of the said aviation kerosene.
The article is to present the experimental testing results of the combustion characteristics of the droplet size distribution of aviation kerosene were with a Winner38 C laser particle size analyzer and the injection system. For the study purpose,we have also designed and constructed a vertical explosive tube by the authors ourselves so as to identify and determined the effects of the droplet size distribution of the combustible liquid on its ignition features of the atmosphere. In proceeding with our experiments,we have first of all managed to measure the variation of the droplet sizes of the aviation kerosene at the different injection pressures of the 5 nozzles. And,secondly,the ignition test of the aviation kerosene droplets has been conducted in the two different firing systems with the initial oxygen concentration being 21%.The results of the afforementioned experiments and tests indicate that,with the increase of the injection pressure the Sauter mean diameter( SMD) of the aerosol droplets tends to decrease,with the minimum SMD of aviation kerosene droplet being of 15 μm. However,the particle size distribution of the mist droplets remains unchanged with the increase of the pressure for the mechanical crushing capacity of the atomizing nozzle would be saturated. Further fuse ignition tests we have done help us to discover that the ignition delay ought to have had a tremendous impact on the combustion of the droplets,for the combustion or explosion of the aviation kerosene droplets is not only related to the particle size,but also is closely related to the concentration of the said droplets,because the height of the flame and the explosion status-in-situ can greatly been influenced and reduced due to the delay of ignition time. For instance,when the concentration of the droplets is reduced to a certain extent,it would not be able to get ignited. A clear example can be seen that,when we conducted the electrostatic ignition tests with the droplets at the ignition energy of 155 mJ,165 mJ,175 mJ,185 mJ and 195 mJ,respectively and correspondingly. Thus,it can be concluded that the ignition energy tends to gradually decrease with the increase of the proportion of the small particle sizes. Furthermore,we have also examined and clarified the relationship between the SMD of D32 and the minimum ignition,which let us believe that there ought to exist a clear inverse proportion between the minimum ignition energy and the SMD of the said aviation kerosene.
引文
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[10] WANG Yue(王悦),BAI Chunhua(白春华). Experimental research on explosion parameters of diethyl ether mist[J]. Explosion and Shock Waves(爆炸与冲击),2016,36(4):497-502.
[11] GUO Mingyue(郭明月). The explosion of the hydrocarbon oil droplets characteristic research(烃类油品雾滴的爆炸特性研究)[D]. Shenyang:Shenyang Aerospace University,2015.
[2] DOUGLAS C,STAMPS A,SCOTT E,et al. Observations of the cellular structure of fuel-air detonations[J]. Combustion and Flame,2006,144(1):289-298.
[3] LEE T W,JAIN V,KOZOLA S. Measurement of minimum ignition energy by using laser sparks for hydrocarbon fuel in air:propane dodecane and jet fuel[J]. Combustion and Flame,2001,125:1320-1328.
[4] WANG Yue(王悦). Research on generation of mists and explosion characteristics for flammable liquid fuels(可燃液体燃料云雾形成和爆炸问题研究)[D]. Beijing:Beijing Institute of Technology,2016.
[5] DING Jue(丁珏),LIU Jiacong(刘家骢). Numerical study on the whole process of explosive dispersal for forming liquid-air cloud[J].Chinese Journal of Explosives Propellants(火炸药学报),2001,20(1):20-23.
[6] RAO K V L,LEFEBVRE A H. Minimum ignition energies in flowing kerosine-air mixtures[J]. Combustion and Flame,1976,27:1-20.
[7] AGGARWAL S K. A review of spray ignition phenomena:Present status and future research[J]. Progress in Energy and Combustion Science,1998,24:565-600.
[8] CHEN Jun(陈军),WU Goudong(吴国栋),HAN Zhaoyuan(韩肇元),et al. Measurement on mean size of liquid droplets of FAE dispersed by explosives[J]. Explosion and Shock Waves(爆炸与冲击),2003,23(1):74-77.
[9] LEI Zheng(雷正),LU Changbo(鲁长波),AN Gaojun(安高军),et al. Experimental study on atomization and combustion explosion characteristics of gasoline[J]. Fire Science and Technology(消防科学与技术),2014,11:1250-1253.
[10] WANG Yue(王悦),BAI Chunhua(白春华). Experimental research on explosion parameters of diethyl ether mist[J]. Explosion and Shock Waves(爆炸与冲击),2016,36(4):497-502.
[11] GUO Mingyue(郭明月). The explosion of the hydrocarbon oil droplets characteristic research(烃类油品雾滴的爆炸特性研究)[D]. Shenyang:Shenyang Aerospace University,2015.